A conventional paper making system comprises a paper forming station for forming a paper web, a coating station for applying a layer of coating material onto the paper web, and a winding station for winding the supplied web onto a spool.
A type of winder is usually employed in the winding station with a horizontal rail frames (referred hereinafter as the "winder"). A paper web is advanced continuously by a feed drum and around a part of the periphery of the feed drum to a windup spool, and is then wound onto the windup spool into a roll. The windup spool contacts the feed drum with frictional rotation, the drum being driven by a drive mechanism. Thus the spool is rotated by the rotating feed drum. When the paper web wound onto the windup spool has a predetermined amount of webbing wound thereon, the supplied paper web is then wound onto a second, a succeeding new windup spool which then replaces the filled up first spool. The second windup spool is maintained in a standby position and is held by pivotable primary arms at a higher level than the feed drum. As the lowering of the primary arms bring the succeeding spool 2b into contact with the feed drum 1, the paper web is ripped along its width by the pressure of a blast of air discharged tangentially to the feed drum 1 so that the ripped following end of the oncoming paper web supply is blown upwardly and is wound onto the second, the succeeding windup spool. The paper webbing wound up onto the first windup spool is transported by a returnable secondary arm which supports the first spool away from where it was wound with the webbing and then the second spool is lowered onto the horizontal rails and is handed over to the secondary arm while it is in frictional, rotating contact with the feed drum.
This technique of ripping the supplied paper web by the air blast produces irregularly shaped ripped paper sections so that the ripped starting edge of the following paper webbing is likely to be folded and then overlapped. This means that the satisfactory winding up of the ripped starting edge onto the second windup spool is not assured because the folded and overlapped edge of the paper web results in an irregular wound up roll that can be deformed at its edges or produces an irregular running out of the wound up paper web due to position deviation. As a result, a finished roll can have relatively numerous poorly wound parts.
The aforementioned known technique, requires long time period to wind the paper web onto the second windup spool if the paper web is too difficult to rip or is so soft that it would be torn at a part which follows the ripped edge wound onto the second windup spool. In such cases which take too much time to wind the paper web that is continuously supplied must be taken away to minimize loss and/or damage, and the required additional labor results in a loss of productivity of rolls of paper webbing.
In view of the aforementioned disadvantages, there was previously proposed an improved technique to enable a regular ripping of the supplied paper web by a discharged air blast, combined with making a transverse slit in the center part of the paper web upstream of the feed drum, and then discharging the air blast onto the slit, as shown in Japanese publication H1-129163 of Japanese utility model application S63-25852 filed Feb. 27, 1988. According to that improved, simplified technique, particularly where a wheel with a slitting knife provided thereon is used to make a lateral slit in the paper web. A slitting wheel is adapted to rotate in contact with the paper web, so that a slitting knife provided on the slitting wheel makes a lateral slit in the paper web, and the discharge of the air jet rips the paper web suitably in a desirable sectional outline.
Even with the improved technique for making a slit in the paper web with a slitting knife, it is not possible smoothly to wind paper web, without folding and overlapping particularly when the paper web is a sheet of relatively stiff paper coated with a layer of thick coating material.